Lebanon's Hezbollah movement said on Sunday it launched its "largest" air operation, sending explosive drones at a mountaintop Israeli military intelligence base in the occupied Golan Heights.
It is the latest incident among escalating cross-border exchanges of fire that have triggered global alarm.
Hezbollah has traded almost daily fire with Israeli forces since the Gaza war began in October.
Announcing "the largest operation" carried out by its aerial forces, Hezbollah said in a statement that its fighters sent "multiple, successive squadrons of drones to target the reconnaissance centre" on Jabal Al-Sheikh (Mount Hermon).
The Israeli military said an explosive drone "fell in an open area in the Mount Hermon area" but there were "no injuries".
Attacks as well as rhetoric have escalated in recent weeks, spurring fears of an all-out conflict between Israel and Hezbollah which last went to war in 2006.
The Lebanese movement said the drone attack was part of its "response" to the killing of an operative in a strike Saturday deep into east Lebanon around 60 miles (100 kilometres) from the border.
The Jabal Al-Sheikh attack targeted intelligence systems, "destroying them and starting a major fire", Hezbollah said.
Israeli Defence Minister Yoav Gallant visited troops on Jabal Al-Sheikh earlier on Sunday, his office said.
In two additional statements, the military said its air defences "successfully intercepted" several "aerial targets" that crossed from Lebanon after sirens sounded in the Golan Heights area.
Israel illegally occupies the Golan Heights and has annexed it in a move largely unrecognised by the international community. Israel seized the territory from Syria in 1967.
The Israeli strike on Saturday killed "a key operative in Hezbollah's Aerial Defence Unit", the military has said.
Throughout Sunday, Hezbollah announced four more attacks on Israeli military sites across the border with barrages of rockets as well as some guided missiles. Israeli authorities reported four wounded.
Gallant, in a video from Jabal Al-Sheikh, said that "even if there is a ceasefire" in Gaza, "we will continue fighting and doing everything necessary to bring about the desired result" in the campaign against Hezbollah.
The cross-border violence has killed at least 497 people in Lebanon, mostly fighters but also including 95 civilians, according to an AFP tally.
On the Israeli side, at least 16 soldiers and 11 civilians have been killed, according to the authorities.
Tens of thousands of residents have been displaced from the border areas in both southern Lebanon and northern Israel.
